Final answer:
The cost of carpeting the floor of the room at the given rate is Rs. 90,000.
Step-by-step explanation:
To find the length of the room, we can multiply the breadth by 3: Length = 3 * 20 = 60ft.
The area of the room is calculated by multiplying the length and breadth: Area = 60ft * 20ft = 1200ft².
To find the cost of carpeting the floor, we can multiply the area by the rate per square foot:
Cost = 1200ft² * Rs. 75/ft² = Rs. 90,000. Therefore, the answer is D) Rs. 90,000.